1. Field of the Invention
The present invention relates to a method of connecting an automotive electrical junction box and wire harness. Specifically, the invention relates to a method whereby the wire harness wires can be connected to the internal junction box circuits with improved assembly efficiency.
2. Discussion of Background Information
The number of circuits contained in an automotive junction box has been increasing lately as a result of the large number of electrical devices that are being installed in automobiles. The high density of branch circuits connected inside the junction box results in an extremely large number of components. This necessitates a correspondingly large number of assembly operations.
FIG. 6 illustrates a structure that has been previously put forth as means of connecting branch circuits to a junction box with the purpose of reducing the thickness of the junction box, allowing the junction box to easily accommodate changes in circuitry, and reducing the number of operations required to connect branch circuits to a junction box.
The aforesaid connected branch circuits consist of wires 3-1, 3-2, 3—3, 3-n etc. (3-n representing any number of additional wires) that form temporarily bundled wire harness 5 to which connector 4 is attached at one end.
Wires 3-1 etc. are arranged on the top surface of insulator board 2 at their other end in a direction that crosses over trunk conductors 1 that are arranged in parallel strips on the lower surface of insulator board 2. Wires 3-1 etc. are welded to specific trunk conductors 1 through windows 2a that are provided within insulator board 2.
This type of branch circuit connecting method provides means whereby the thickness of the circuit structure can be decreased, circuit assembly operations reduced, and branch circuit modifications easily executed by changing the location of the aforesaid solder windows.
The aforesaid method of connecting a wire harness to the internal circuitry of a junction box is conducted with the wire harness partitioned and temporarily bundled into many leads that extend to destination points for a specific electrical system. Connecting this type of temporarily bundled and partitioned wire harness to the circuits within the junction box largely limits the branch wire connecting structure, makes circuit design extremely difficult, complicates circuit layout, and makes the welding operation unnecessarily difficult due to the wire harness being in a finished but temporarily bundled condition at the time it is connected to the circuits in the junction box.
Furthermore, at the time when the wires of the temporarily bundled wire harness are led through the insulator board and welded to the electrically conductive material located on the opposite side of the insulator board, the efficiency of the welding operation is adversely affected because the total weight of wire harness 5 is applied to the wires being welded, a problem that results from the other ends of the aforesaid wires being attached to connectors and other wires through those connectors.
The present invention considers the aforesaid shortcomings relating to wiring structures in which electrical leads from a wire harness are directly connected to circuits within a junction box, and proposes a method by which branch circuits emanating from the junction box can be easily structured, and a method by which the amount of labor needed for the wire connection operation can be reduced.